Reduction in antiviral activity of human interferon-gamma in acidic media with reference to structural change

The fluorescence intensity of a unique tryptophan 36 in human interferon-gamma was drastically decreased below pH 4 with a concomitant decrease of antiviral activity. The region of residues 32-42 of human interferon-gamma was found by calculation to have a low hydrophobicity together with a high helical hydrophobic moment, and the net electric charge of this region having an amphiphilic helical structure changed significantly near pH 4. These results suggest that the region of residues 32-42 plays an important role in exhibiting antiviral activity.     

A case of diverticular disease of the colon in a Japanese monkey (Macaca fuscata)

Diverticular disease of the colon was detected in a female Japanese monkey by X-ray examination. The monkey was 15 years old and had been kept under captive conditions for nine years. Lack of appetite and activity, and constipation were observed. The monkey was given fiber-rich vegetables and wild plants, and its appetite and activity then improved. Based on a consideration of various factors, it is suggested that one possible cause of the diverticulosis in this case was a low dietary fiber intake.     

Gene structure of human thrombomodulin, a cofactor for thrombin-catalyzed activation of protein C

The gene coding for human thrombomodulin, a thrombin receptor on endothelial cells and a cofactor for the activation of anticoagulant protein C zymogen, was isolated from a human genomic library by employing human thrombomodulin cDNA as a probe. The nucleotide sequences of the gene and the adjacent 5' and 3' flanking regions were then determined. The nucleotide sequence of this gene with approximately 3.7 kilobase pairs was identical to that of the cDNA, indicating that the gene for human thrombomodulin is free of introns. Hybridization data showed that there is only a single thrombomodulin gene in the human genome.     

Ontogenesis of gastrin cells in the pyloric antrum and duodenum of the mouse

Summary Ontogenesis of gastrin cells was studied in the pyloroduodenal mucosa of the mouse using anti-human G17 serum, R-1301, and anti-human G34(1–15) serum, R-2703. R-1301-immunostained cells first appeared in the pyloric mucosa of 14-day-old fetuses. Cells stained with both R-1301 and R-2703 appeared immediately after birth, and gradually increased in number to the adult level. Most R-1301-reactive cells were also reactive to R-2703, whereas some cells that reacted with R-1301 exhibited very weak or no reaction with R-2703. The discrepancy between these two immunoreactivities is discussed.In the duodenum, a considerable number of R-1301-reactive cells were present from the perinatal stage and through out adult development. A few R-2703-reactive cells were seen in the duodenum of young mice but not of the adult.     

Endotoxic properties of chemically synthesized lipid A analogs. Studies on six inflammatory reactions in vivo, and one reaction in vitro

Biological activities of two groups of synthesized lipid A analogs, the counterpart of biosynthetic precursor, Lehmann's Ia type, 406, and E. coli lipid A type, 506, as well as their non-phosphorylated, and mono-phosphorylated analogs were investigated. The activities employed included four bone marrow cell reactions in mice, mice skin reaction, leukocytes migration in rabbits' cornea, and hemagglutination. Compound 406 and 506 elicited bone marrow reactions in mice and hemagglutination of mouse RBC, although 406 failed to elicit hemorrhage and necrosis also in mice skin. Compound 406 did not elicit corneal reaction in rabbits. The results suggest that for elicitation of this reaction and mice skin reaction, acyloxyacyl structure is required. Cytotoxicity and thromboplastin production of four bone marrow reactions had been reported by us to be endotoxic reactions, since these had not been elicited by peptidoglycan of Lactobacillus and Staphylococcus (1981) and 300 series synthesized analogs (1984) which did not have endotoxic structures. From these results, it seems that these two marrow reactions and hemagglutination require, as does the limulus test, the lipid A part structure as is present in 406.     

In vitro neurotoxicity of amyloid β-peptide cross-linked by transglutaminase

Transglutaminase catalyzes the intermolecular cross-linking of peptides between Gln and Lys residues, forming an -(-glutamyl) lysine bond. Amyloid -peptide, a major constituent of the deposits in Alzheimer disease, contains Lys16, Lys28, and Gln15 which may act as substrates of transglutaminase. Transglutaminase treatment of amyloid -peptide (1–28) and amyloid -peptide (1–40) yielded cross-linked oligomers. Transglutaminase-treated A retarded neurite extension of PC12 cells, and rat cultured neurons of hippocampus and septum, brain areas severely affected by Alzheimer disease, and subsequently caused cell death, whereas the transglutaminase-untreated counterparts did not show harmful effects. The transglutaminase-catalyzed oligomers of amyloid -peptide and their neurotoxicity may be involved in two characteristics in Alzheimer disease, neuronal degeneration and formation of the insoluble deposits.Abbreviations: AD – Alzheimer disease, A – amyloid -peptide, DMEM – Dulbecco's modified Eagle's medium, DMEM/F–12–1:1 mixture of DMEM and Ham's F–12 medium, FCS – fetal calf serum, HS – horse serum, PAGE – polyacrylamide gel electrophoresis, MTT – 3-(4,5-dimethylthiazol–2-yl)–2,5-diphenyltetrazolium bromide, NGF – nerve growth factor, TGase – transglutaminase.     

Characterization of monoclonal antibodies recognizing three distinct, phosphorylated carbohydrate epitopes in the lipopolysaccharide of the deep rough mutant I-69 Rd−/b+ of Haemophilus influenzae

Monoclonal antibodies against the lipopolysaccharide (LPS) of the deep rough mutant I-69 Rd⁻/b⁺ of Haemophilus influenzae were obtained after immunization of mice with sheep erythrocytes which had been coated with de- O -acylated LPS. Characterization of antibodies was performed by enzyme immuno assay (EIA) using LPS or neoglycoconjugates containing partial structures of LPS as solid-phase antigens and by haemagglutination with sheep erythrocytes coated with de- O -acylated LPS. Binding data were confirmed by EIA inhibition experiments using deacylated LPS or synthetic partial structures thereof. Three antibodies were specific for 3-deoxy- d - manno -octulopyranosonic acid- (Kdo) 5-phosphate, one for Kdo-4-phosphate, and one required, in addition to a Kdo-phosphate, parts of the phosphorylated glucosamine backbone of lipid A. All antibodies also bound in (i) Western blots to bacterial whole-cell lysates or isolated LPS separated by SDS–PAGE, (ii) bacterial colony blots, and (iii) immunofluorescence with live bacteria. The latter result indicated that Kdo-4- and Kdo-5-phosphate are synthesized by the bacteria and are not the result of phosphate migration.     

Differential Localization of the γ3 and γ12 Subunits of G Proteins in the Mammalian Brain

Abstract: The localization of two forms of the γ subunit of G proteins, γ₃ and γ₁₂, was examined in the mammalian brain. Concentrations of these two γ subunits increased markedly, as did those of glial fibrillary acidic protein, during postnatal development in the rat cerebral cortex. In aged human brains, by contrast, the concentration of γ₃ tended to decrease with age, whereas that of γ₁₂ in the temporal cortex increased slightly. An immunohistochemical study of human brains revealed that γ₃ was abundant in the neuropil, whereas γ₁₂ was localized in glial cells. In the hippocampal formation of aged human brains, levels of γ₁₂-positive cells, as well as levels of glial fibrillary acidic protein- and vimentin-positive astrocytes, increased, in particular in the CA1 subfield and the prosubiculum, in which there was a decrease in the number of pyramidal cells. The appearance of γ₁₂-positive cells associated with the loss of pyramidal cells was also observed in the hippocampus of rats that had been treated with kainic acid. These results indicate that γ₁₂ is strongly expressed in reactive astrocytes. In a study of cultured neural cells, we found that γ₁₂ was predominant in glioma cells, such as C6 and GA-1 cells, in contrast with the specific localization of γ₃ in PC12 pheochromocytoma cells, which are neuron-like cells. Taken together, the results indicate that γ₃ and γ₁₂ are selectively expressed in neuronal and glial cells, respectively, and that concentrations of γ₃ and γ₁₂ in the brain are related to the numbers and/or extent of maturation of these cells.     

Two Forms of GO Type G Proteins: Identification and Distribution in Various Rat Tissues and Cloned Cells

A G(o) type G protein distinct from the major species of G(o) was recently isolated from bovine brain and designated G(o)*. The cDNAs encoding two forms of mammalian G(o) alpha were also isolated and designated GoA alpha and GoB alpha. To recognize two forms of G(o) type G proteins, we raised antibodies in rabbits against two peptides with sequences found only in the respective proteins of murine GoA alpha (SNTYEDAAAYIQTQF) and GoB alpha (TEAVAHIQGQYWSK). Purified anti-GoA alpha antibodies reacted with the major species of G(o) alpha purified from bovine and rat brain, whereas anti-GoB alpha antibodies reacted only with rat G(o)*alpha, but not with the major species of G(o) alpha or bovine G(o)*alpha. These results indicate that the major species of G(o) alpha is encoded by GoA alpha cDNA and G(o)*alpha is encoded by GoB alpha cDNA. Using these antibodies, the distribution of GoA and GoB was studied in various rat tissues and cloned cells. Both GoA and GoB were present in many tissues, but their distribution in peripheral tissues was distinct. GoA alpha seemed to associate mainly with neural tissues. On the other hand, relatively high concentrations of GoB alpha were present in the brain, pituitary gland, adipose tissue, lung, and testis. The concentrations of both GoA and GoB in the brain increased during ontogenic development, but the increase in GoB was observed at a later age. Both GoA and GoB were found in such cloned cells as PC12, NG108-15, C6, GA-1, G8, and 3T3-L1 cells. Treatment of PC12 cells with nerve growth factor caused the extension of neuron-like processes and the increase in the level of GoA, but not in the level of GoB.